Renal Agenesis / Hypoplasia (name no longer used: Potter Syndrome)
Renal agenesis is the name given to a condition that is present at birth that is an absence of one or both kidneys. The kidneys develop between the 5th and 12th week of fetal life, and by the 13th week they are normally producing urine. When the embryonic kidney cells fail to develop, the result is called renal agenesis. It is often detected on fetal ultrasound because there will be a lack of amniotic fluid (called oligohydramnios).
When both kidneys are absent this condition is not compatible with life. 40% of babies with bilateral renal agenesis will be stillborn, and if born alive, the baby will live only a few hours. Babies with bilateral renal agenesis will have several unique characteristics: dry loose skin, wide-set eyes, prominent folds at the inner corner of each eye, sharp nose, and large low-set ears with lack of ear cartilage. They will typically have underdeveloped lungs, absent urinary bladder, anal atresia, esophageal atresia, and unusual genitals. The lack of amniotic fluid causes some of the problems (undeveloped lungs, sharp nose, clubbed feet) and other problems occur because the kidneys and those affected structures are formed at the same time of fetal life (such as the ears, genitals, esophagus).
Babies with unilateral renal agenesis (absence of one kidney) may have no other symptoms at all. Unilateral renal agenesis is more common with intrauterine growth retardation (poor growth during pregnancy) and often results in premature birth. It is also more common when a mother is carrying more than one baby (multiple gestations, such twins, or triplets). Children with unilateral renal agenesis will generally live normal lives with no developmental effects. In fact, many times the solitary kidney is only detected incidentally when x-rays are done for other purposes. The remaining kidney will enlarge to carry out the function normally done by two kidneys.
Bilateral renal agenesis occurs in 1 of 4500 live births and is usually found in boys. Unilateral renal agenesis occurs in 1 of 1000-2000 live births. Usually there is no family history of renal agenesis, but in 20-36% of cases, there is a genetic cause.
Using data from Minnesota births between 2014-2018, we found 210 babies were born with renal agenesis/hypoplasia, resulting in a rate of 6 babies per 10,000 births. Annually, about 42 babies were born with renal agenesis/hypoplasia.
Parental education and support are essential, and local, regional, and national organizations may be very helpful.